With increased market pressure on reducing excavation machine fuel consumption and improving both the effectiveness of novice operators and the comfort for all operators, control strategies that optimize machine performance while still providing the required machine controllability are becoming more important. One particular opportunity may be associated with boom control during both digging and leveling operations. During these operations, improper boom control can lead to excessive fuel burn because either insufficient payload is acquired, the stick and/or bucket stalls during digging, or the boom cylinder head end pressure drops too low causing additional hydraulic losses. Improper boom control during the digging or leveling operations may also cause rocking or jerking of the machine, resulting in instability and discomfort of the operator.
One attempt to improve the digging efficiency of an excavation machine is disclosed in U.S. Pat. No. 7,979,181 (“the '181 patent”) that issued to Clark et al. The '181 patent discloses a machine that automates the digging cycle by controlling the bucket and boom velocity dependent on the relative hardness of the work material. An electronic signal queries whether the bucket tip is at a desired dig angle. If not, the control initiates a boom-up command to assist in curling the bucket. The control of the '181 patent automates the speed of the bucket and the boom depending on the relative hardness of the material.
Although the '181 patent may provide some improvements on the digging cycle, it may also have some drawbacks. Specifically, the automated system may lack broad applicability to a manned machine. The automated system also may not benefit a novice operator or improve the comfort and safety of the operator.
The hydraulic control system of the present disclosure solves one or more of the problems set forth above and/or other problems in the art.